"Power limit doesn't matter as card is boosting to its max frequency when framerate is unlocked."

This has nothing to do with it. This has to do with the power draw any card has when put under heavy load. The default setting (0) is a power saving feature. The +20/+50 Power limit setting disables the default throttling.

After messing around with the settings in the game, especially MSAA/FXAA settings, it does not seem to take effect in the game at all.

And sometimes when I turn on MSAA I get same problem with flickering "black square" boxes In the treeline, this issue was fixed back in 17.5.1 I belive, but is back now, that being said, I did not notice this bug before 17.5.2, never had this issue.

In all Honesty, with the release of the Hot Wheels DLC i actually have improved Performance with the 17.5.2 over the .2.1, before the DLC I had about 70 FPS with the .2.1, after the DLC I had around 70-80 fps and stuttering hell with artifacts using the 2.1, with the 17.5.1 I have around 100-120 fps.

the thing is that I had to disable ReLive Instant Capture features for FH3 because it was causing stutters every few seconds. Sadly the HW DLC made the stability go to hell instead, the game crashes at least once per hour, I get Disconnects for no reason from Online Adventures and so on.

I don't really know which side is causing it so I wrote in both forums because I had some odd VRAM warnings when there still was about 4-3gb of VRAM left to use.

I think that FH3 is just terrible optimized for AMD which is kinda laughable considering that the entire Xbox One is based around AMD Hardware..... well since it is being Investigated, hope you can find something out.

Well, after I've read this today I updated to the new clean 17.9.1 driver from a 17.7.1 driver modified with the DLL trick and I've got the performance issues again on my R9 290 just like with older drivers without using the DLL trick.